Do I need to turn on cellular data on my iphone when using USA $7/day roam in the USA to use data?

When I use my iphone in the USA for the $7/day roam do I have to switch the cellular setting in my Iphone under cellular data options to "roaming on"? I recently used my phone in the usa for texting with the $7/day plan but was uncertain as to what implicationschanging my cellular data setting to roaming while in the USA would do in terms of charges. Somewhere I read that Koodo says use your phone just like in Canada when roaming however I do not have my cellular data option for roaming turned on when I am in Canada. I am confused can someone enlighten me? thanks